One-year follow-up of infants exposed to ultrasound in utero.

Neonatal and infant follow-up data from the Amniocentesis Registry of the National Institute of Child Health and Human Development were analyzed for possible effects of diagnostic ultrasound exposure in the second trimester of pregnancy. A total of 297 infants of mothers receiving both amniocentesis and diagnostic ultrasound were compared with a similar group of 661 infants of mothers who had amniocentesis but not ultrasound and with 949 infants exposed to neither amniocentesis nor ultrasound. Results of newborn and 1 year examinations were similar for the amniocentesis with ultrasound group when compared to the other two groups. However, in view of the small sample size and other limitations of these data, larger and more detailed studies are needed to adequately assess possible effects of ultrasound in pregnancy.